French patent specification No. 1,223,862 discloses a connector of the above type allowing a securing of a table leg provided with an internal thread to a tabletop. The connector comprises a screw and a bushing with an external thread. The bushing is secured to the tabletop by the screw being inserted therethrough and screwed onto the tabletop. Subsequently, the table leg is screwed on the bushing by being turned about its longitudinal axis until it abuts the tabletop. A disk is optionally inserted between the bushing and the tabletop, said disk preventing a rotation of the bushing when the table leg is screwed thereon. This connector is, however, not quite satisfactory because two or three loose parts, viz. the bushing, the screw, and optionally the disk, are involved in the assembling of the table leg and the tabletop, which causes a strenuous mounting procedure. Furthermore this connector is encumbered with the draw-back that it is impossible to perform a subsequent adjustment of the turning angle of the table leg when said leg is secured to the tabletop. When a subsequent adjustment is attempted, the tightening force is changed.
The object of the invention is to provide a connector of the above type without loose parts and allowing an assembling of two structural members by a predetermined joining force, and which further allows an angular adjustment of one structural member relative to another structural member within a minor angular interval without thereby changing the joining force which should be of a suitable size.
The connector according to the invention is characterized in that the bushing is turnably mounted on a smooth portion of a shaft and fixed in axial direction, one terminal surface of the bushing abutting the head of a screw and the opposite terminal surface of said bushing optionally abutting a locking means projecting from the shaft, and that one of the terminal surfaces of the bushing comprises a contact knob delimiting the turning of the bushing relative to the screw to an angle less than 350.degree. when abutting a stop projection projecting from the screw.
When two structural members (such as a table top and a table leg) are to be assembled, the bushing is initially secured to one structural member, whereby care is taken that the thread on the screw projects outside the structural member. Subsequently, the structural member and the connector can be secured as a unit onto the second structural member by being screwed into a hole therein. The screwing inwards is continued until the desired joining force has been obtained. Then the first structural member can be turned about the smooth portion of the shaft and consequently relative to the second structural member without reducing the joining force because the bushing can be turned backwards relative to the screw without causing an axial displacement between said bushing and the screw. This turning backwards can, however, only be performed over an angle less than 350.degree., said angle depending on the position and the size of the stop projection and the contact knob. The connector is furthermore very useful in practice because all the parts are interconnected and appear as a compact unit. The connector turned out to be particularly suited for assembling a table leg of a cross section corresponding to a right-angled triangle to a rectangular tabletop. In the latter case there is only one correct angular position of the table leg, i.e. in its rotation about its longitudinal axis, relative to the tabletop as it is assumed that the table leg is placed adjacent the corner of the tabletop. This is due to the fact that the right angle of the triangle must correspond to the right corner angle of the tabletop.
According to the invention the connector may be free of the locking means, and the stop projection may be situated on the screw in such a manner that beyond serving as a stop for the angular rotation of the bushing relative to the screw it locks the bushing axially relative to said screw.
Moreover according to the invention the stop projection may substantially be formed by a projection projecting from the shaft and as a maximum projecting as far outwards in the radial direction as the bushing. In this manner the connector is inexpensive to manufacture and functions reliably.
Furthermore according to the invention the contact projection may substantially be formed by a projection extending axially from the second terminal surface of the bushing, the axial length of said projection substantially corresponding to the dimension of the stop projection in the axial direction of the screw, optionally slightly smaller than said dimension. Such an embodiment turned out to be very advantageous in practice.
In addition according to the invention the stop projection may be of such a thickness that it allows a maximum turning of the bushing of 340.degree., preferably 330.degree., about the screw, whereby the structural members can be angularly adjusted relative to one another in a very easy manner.
Moreover according to the invention the holding means of the bushing may be threads, and the shaft may comprise a preferably transverse hole in the area between the thread of the screw and the bushing, said hole receiving a mounting tool when the bushing is to be screwed into a hole of the first structural member. As a result the bushing is very easily mounted in one structural member such as for instance the table leg.
As the bushing is secured into the first structural member through casting therein before the screw is turned into the second structural member, said first structural member for instance being made of plastics, a very simple securing of the bushing in the first structural member such as for instance the table leg is obtained.
Furthermore according to the invention a resilient member such as a washer may be provided between the first terminal surface of the bushing and the head of the screw in order to achieve an axial prestressing between the bushing and the screw, which provides a certain resiliency between the two structural members.
Moreover according to the invention the bushing and the associated projection may be integral with the table leg, and the stop projection may be situated on the head of the screw and optionally be integral therewith, whereas the contact projection is situated on the terminal surface of the bushing facing the head of the screw, and the locking means may be formed by a locking disk preferably cut up and situated on the screw, preferably through mounting in a groove in the shaft of the screw. As a result the bushing and the associated contact projection can be manufactured simultaneously with the table leg in a very simple manner.
Finally according to the invention the bushing may be secured to the table leg by means of ribs projecting from the walls of the table leg, said ribs preferably projecting from the bushing, and one of these ribs, projecting slightly beyond the remaining ribs, may form the contact projection. In this manner a simple embodiment of the bushing, the contact projection, and the table leg is obtained, whereby these parts can be manufactured for instance through casting.